1. Field of Art
The present invention relates generally to a ceramic structure defining a divided combustion chamber of an internal combustion engine, ad more particularly to an improved structure consisting of a plurality of ceramic members which cooperate to define a divided combustion chamber of an internal combustion engine for automotive vehicles.
2. Related Art Statement
There have been made heretofore a number of attempts to use a ceramic material for a divided combustion chamber of an internal combustion engine, such as a swirl or pre-combustion chamber of a Diesel engine. For example, the use of various ceramic materials having excellent heat resistance and high strength at an elevated temperature, such as silicon carbide or nitride, has been proposed for improving the durability of the cup structure of the swirl chamber which is formed with a gas passage communicating with the main combustion chamber of the Diesel engine. In the recent years, it has been proposed to form the entire structure of such a swirl chamber of a ceramic material, with a view to ensuring improved fuel economy or thermal efficiency of the engine, by utilizing the heat insulating properties of the ceramic material, which contribute to maintaining a higher temperature of the combustion gas within the swirl chamber.
In the case where a divided combustion chamber is wholly formed of a ceramic material, like the swirl chamber indicated above, the structure defining the chamber generally consists of a plurality of separate ceramic members which are assembled so as to cooperate to form the chamber therein. Usually, the assembly of the ceramic members defining therein the divided combustion chamber is retained in the cylinder head of the engine, by the inner wall of the cylinder head if the assembly is directly received in a recess formed in the cylinder head, or alternatively by an external metallic ring or sleeve which is disposed in the recess and is fitted on the outer surface of the assembly.